Signaling system



Aug. 4, 1925.

J. J. GILBERT SIGNALING SYSTEM Filed Nov. 14. 1921 I H. Tc

Patented Aug. 4, 1925.

' 'UNITED STATES PATET OFFICE.

JOHN J. GILBERT, OF PORT WASHINGTON, NEW YORK, ASSIGNOR TO WESTERN ELEC-TRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEWYORK.

SIGNALING SYSTEM.

Application filed November 14, 1921. Serial No. 514,845.

To all whom it may concern:

Be it known that I, JOHN J; GILBERT, a citizen of the United States,residing at Port Vashington, in the county of Nassau,

State of New York, have invented certain new and useful Improvements inSignaling Systems, of which the following is a full,

clear, concise, and exact description.

This invention relates to telegraph systems and more particularly tosubmarine cable telegraph systems. v p

In duplex telegraph systems where current impulses are transmitted overa single conductor in opposite directions simultaneously,

it is impossible to secure and maintain a perfect balance between thereal and artificial lines; Consequently considerable difficultyisexperienced 'owingzto disturbances caused by theinitial surge ofcurrent'due'to a change ofpolarity applied to the signaling conductor,whichjtends to effect distortion of the incoming signals,and whichmay-haven harmful'effec't upon the subsequent'action of the apparatusused in correcting and amplifying the received signals. j

The principal object of this invention is the minimizing of the effectsof such disturbances. i In carrying out this object there is preferablyprovided means associated with the signaling system utilizing duplexequipment whereby the receiving instrument may be alternatelyoperatively connected with, and disconnected from, the real andartificial lines. p

Other objects of the invention will hereinafter appear. y v

In the drawing, Fig. 1 isa digrammatic ilhistration of a duplex cablesystem embodying the invention; Fig. 2 shows a curve use ful indescribing the operation thereof; and Fig. 3 shows a special applicationof the invention to high speed signaling systems employingtransmittingand receiving distributors.

Referrin-gfirst to Fig.2, a typical case of unbalance is illustrated,the curve A, B, C. D representing the current in the receivinginstrument atone end of the line due tovoltage applied to the duplexnetwork by the transmitter at the same end of the'line during theinterval AE. Theportion A, B, C usually occupies only a small fractionof this interval, but on account of its large amplitude, it mayinterfere seriously with the incoming signals. The remainder of the unbalance C, D is of comparatively small ambridge is represented by anartificial balanc-' ing network 7 comprising suitable resistances'andcondensers connected to ground in the usual manner, the usual condensers8 and 9 being provided in .the twoother arms of the bridge. In thebridge is an amplifier or shaping and correcting network 10 connected tothe windings of a polarized relay 11 which, in turn, controls a localcircuit including a source of current 12 and a recording instrument orsounder 13. The transmitter may include a rotatable drum let, aperforated tape 15 and associated brushes i6, 17 and 18. Associated withthe transmitting drum members are neutral relays 19 and 20 andenergizing batteries 21 and 22 for controlling a battery 23, in themanner well understood in the art, to impress currents ofeither polarityupon the line It is common practice in systems of duplex and multiplextelegraphy to connect the amplifying network 10 and receiving relay 11directly across the arms 6 and 7 of the bridge, the accuracy of thesystems depending upon the artificial network 7 which should haveexactly the same electrical resistance and capacity as the real line 6.In ac cordance with the present invention, however, only one terminal ofthe receiving ap paratus is permanently connected in the bridge, as'at2t,fthe other end being connected in such a way that it may alternatelybe connected to and disconnected from the bridge. This is accomplishedin the present case bymeans of a brush 25 in circuit with the artificialnetwork 7 and a brush 26 in circuit with the amplifying network 10,these brushes being adapted for alternate engagement with conductingsegments 27 and the non-conducting surface of the distributor frame 28.When the brushes 25 and 26 rest upon conducting segments 27, as shown inthe drawing, the receiving relay 11 is connected through the amplifyingnetwork 10 to the artificial balancing network 7, and when these brushesrest on the non-conducting surface 28, the receiving apparatus is insulated from the duplex DQtWOIK. The dis- 65 is connected, it wouldsimply be necessary eflfifa e lestns oil a e m n 2 a d t e tribut oijpreferablypositioncd on the rotatable transmitting druiiii 14. Theuniform conducting segments 27 aresliorter" thaii the tape" perforationsin the transmit" tingtape 15' and are so oriented with respect to theperforations that the transmitting brush 17 or 18 will enter upon the'conducting surface of the drum 14: in advance of the entrance of thebrushes" 25 and 26 1116611 arseg nent Q'Y. flhus, asthe drum l4isrotated past the stationary brushesn the receivli s nem m i tl 'b inlet from t e network atgthe beginning of each impulse ..dnring thetirneAC, at whiolitime the dis? turbance :c lueto unoalance; would bereceived.

receiving 11 connected in operative:

r am wi h. t efjdur r ret re-: d s? sramhe. i@sem,- nd m y'beltj i l-tReferr ng no w to the modificat on shown nangemen't shown in Fig. isemployed, but

nn eee ifh ape, t ansmi and c v- 25 ts soun r, Le, eyneli e qe d s u iemployed ate e 1 en it e e' Hov in 91 's e gmen fifirnt he istr n e i ius d e transm t ing?si n s; the ee i i this.

1 asher-1e iim fe mlee e A secondrins eiz eeme i ll is: p vided e P13 19rame: 23 has ed. fib rs," yr i t 9f:

. c .7 t n rele i lt S..a 'B -t yn nsu at -f refi l d eennee ed t9 t itba- 'ane ia netw r 7 h rd in Oi rec v n se me t '12 is a p o i e ea h;gm nt brine e e ica y s eet ii Wit tan re ie fomagi et of t n i 3.,.13h.et relfiren m i.7 dap e .17

impresses ur entsp e t e pe l r fyfiwm a-s i a-b-l sour :upenthelinerqeim terl with" he; tra tt ng s gm n s t e usua ma nerith-Ah? tra isn ttinei. nts th brush 3 m gm nts 3.0, and eb i fi ed fro-m operativerelation with the filllf plex' network during the very first part ofeach, "gna' 'ling impulse, or at the time when due to unbalance thegreatest disturbance would ordinarily be received.

1 At all other times, however, the receiving' instrument 1s connected totheeleo trical'network and signals froin the distant endmay be received;In order that any desired portions of the'received signal will a r riveat a time when the receiving instrument The bru 3. ie-l e j i i e r 01nit receivihlgl or transmitting rings on the distant distributor to beoriented properly with respect to the segments of the transmitting orreceiving distributor at the near end. By. mutual arrangement "bothreceiving instruments may be freed from the efict of unbalance.

What. is claimed is 1. The method of eliminating disturbances due toduplex unbalance in cable telege raphy whioln comprises" automaticallydis connect ngv the receiving apparatus from operative relation withtliedupl'ex network; during the time' when the iiiii jo'r' portion of"the disturbance is received, and at" all other times automaticallymaintaining tlie receiving instrument in o erative relation with the d hplex'network. l l

21' he method of eliminating distiiibano es diie to duplx' unb lance in05 516 telegrapl y which comprises reinovingfthe receivmg apparatus fromoperative relation-:

ship withthe duplex network at or sli%htl y before the instant mar;large unba potential to the artificial line by'the trans}balancegcurrent" flowing, and at al other times durmg'the transmissionof signals current is produced by the application of maintaining thereceiving inflame-newer:

wa Qeeeete w t th de f 3. 1e combination with a telegraph line of a.duplex network at:each terminalconi prising an artificial nae; means ateach terminal for applying signaling potential to said line,rreceivingapparatus at each terminal; means fo'r stopping reception at eachterminal during-a portion at least. of the time sendin'g'l from that,terminal occurs whereby the effect of imperfect aapiex bridge balanceis! decreased, and meai'isffor J maintaining synchronisni between saidstop pingmeans at the two terminals.

4. Ina telegraphsy'stem,' an'iaii'i line, an artificial line, means forapplyinj signaling potential to said main and arti 'cial lines,receiving a p aratus, and means for auto matically removing saidreceiving apparatus froni'operative relationship with said mificial.line at orslightly before the instant that large unbalance currentispro'duced by the application of saidsignaling'potential to theartificial line and for maintaining said receiving apparatus inoperative relationship with said artificial line lat all other timesduring the transmission of signals. V v s p 5'. I nza telegraph system,a main li e, an artificial line, a bridge' connectinlg" the main andartificial lines; a receiving instruk equallength, and means foralternately and i regularly disconnecting said receiving instrumentfrom, and connecting it to, said bridge, each period of disconnectionbeginning at or slightly before the instant of application to saidbridge of each signaling potential impulse.

6. In a telegraph system, a main line, an artificial line, a bridgeconnecting the main and artificial lines, a receiving instrument in saidbridge, a distributor for impressing signaling potentials upon saidbridge and for alternately and operatively inserting said receivinginstrument in and removing it from said bridge synchronously With theimpression of signaling potentials upon said bridge.

7 In a telegraph system, a main line, an

JOHN J. GILBERT.

